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For implementing ISA, I think you'd probably need some sort of CPLD. I haven't looked, but I suspect they don't make interface devices for those older standards anymore.
If you're willing to roll your own interface, or look around for a few, you'll probably find more success.
65SIB might be worth looking at, as might
SPI-10 and
I2C-6. Those last two aren't meant as an expansion bus as much as 65SIB is, though.
What chip you use would depend on what kind of interface you want.
If you want a parallel interface, you could use a 65c22. You might need supporting hardware to increase your I/O addressing beyond 256 bytes, though.
If you're OK with a serial interface, the 65SPI might be worth a look, although that's a CPLD firmware.
I don't know enough about the BT81x to say much of anything, really. I did look at using a Gameduino 3, which presents an ordinary SPI interface, but that's out of stock at the moment. It's also quite different to what you appear to be shooting for(the GD3 provides its own display). I'm not sure if these EVE chips can drive a monitor. I've only ever seen them paired fairly closely with an LCD panel.
I can second what Garth said about not needing a logic analyzer. I still don't have one, and I've gotten my SBC running without it. I've wished I had one, but I never actually needed it.